A field study of kick injuries to the radius and tibia in 51 horses (2000-2010).

The objective of this study was to examine all kick injuries to the radius and tibia seen in an ambulatory setting over an 11-year period in order to determine factors affecting outcome. Medical records of 51 horses seen for a kick injury to the radius or tibia were reviewed. Signalment, physical examination findings, type of management, and outcome were evaluated. There was a significant association between the presence of bony crepitus and a lameness score of ≥ 4/5 and a poor outcome. There was no relationship between signalment and outcome, but significantly more Thoroughbred/Thoroughbred cross horses were affected than any other breed. There was no detected relationship between the type of management and outcome; however, most (81%) horses were managed on stall rest. Horses with bony crepitus or with a lameness score of ≥ 4/5 were at an increased risk for euthanasia.

Une étude sur le terrain des blessures de ruades au radius et au tibia chez 51 chevaux (2000­2010). L'objectif de cette étude consistait à examiner toutes les blessures de ruades au radius et au tibia observées dans un milieu ambulatoire pendant une période de 11 ans afin de déterminer les facteurs qui affectent les résultats. Les dossiers médicaux de 51 chevaux examinés pour une blessure de ruade au radius ou au tibia ont été examinés. Le signalement, les constatations de l'examen physique, le type de gestion et les résultats ont été évalués. Il y avait une association significative entre la présence d'une crépitation osseuse et une cote de boiterie ≥ 4/5 et un résultat défavorable. Il n'y avait aucun lien entre le signalement et le résultat, mais un nombre significativement supérieur de chevaux Thoroughbred/Thoroughbred croisés étaient touchés par rapport à toute autre race. Il n'y a eu aucun lien détecté entre le type de gestion et le résultat; cependant, la plupart (81 %) des chevaux étaient gérés lors d'un repos en stalle. Les chevaux avec une crépitation osseuse ou une cote de boiterie de ≥ 4/5 présentaient un risque accru d'euthanasie.(Traduit par Isabelle Vallières).

Theoretical and experimental investigation of the energetics of cis-trans proline isomerization in peptide models.

The energetics of cis-trans proline isomerization in small peptide models have been investigated using the hybrid density functional theory method B3LYP with a 6-31+G* basis set. The molecules studied are models for the phospho-Ser/Thr-Pro substrate for Pin-1, a peptidyl-prolyl isomerase (PPIase) involved in cell division. Pin-1 requires phosphorylation of a Ser or Thr residue adjacent to a Pro residue in the substrate and catalyzes cis-trans isomerization about the proline amide bond. The dihedral angle that would correspond to the reaction coordinate for isomerization of the omega peptide bond was investigated for several small models. Relaxed potential energy scans for this dihedral angle in N-methylacetamide, 1, N,N-dimethylacetamide, 2, acetylpyrrolidine, 3 and acetylproline, 4, were carried out in 20 degrees steps using the B3LYP/6-31+G* level of theory. In addition, similar scans were carried out for 1-4 protonated on the acetylamide carbonyl oxygen. Optimized structures for 1-4 protonated on the amide nitrogen were also obtained at B3LYP/6-31+G*. Relative proton affinities were determined for each site at various angles along the reaction coordinate for isomerization. The relative proton affinities were anchored to experimental gas phase proton affinities, which were taken from the literature for 1 and 2, or determined in an electrospray ionization-quadrupole ion trap instrument using the extended kinetic method for 3 and 4. Proton affinities of 925 +/- 10 and 911 +/- 12 kJ/mol were determined for 3 and 4, respectively. These studies suggest that the nitrogen atom in these amides becomes the most basic site in the molecule at a dihedral angle of ca. 130 degrees . In addition, the nitrogen atoms in 2-4 are predicted to attain basicities in the range 920-950 kJ/mol, making them basic enough to be the preferred site for hydrogen bonding in the Pin-1 active site, in support of the proposed mechanism for PPIases.